As is well known, a scroll-type compressor comprises a pair of scroll members each of which comprises a base plate and a perpendicular wall having a vortex shape formed on the base plate the perpendicular walls defining a compression. One of the pair is an orbiting scroll member, and the other is a stationary scroll member. These two scroll members are located to match with each other. By eccentrically revolving the orbiting scroll member, a fluid is compressed in the compression chamber enclosed with the vortex walls. In such a scroll-type compressor, as disclosed in JP-A-50-32512, JP-A-55-81296 and so forth, a long sealing material in a vortex shape is provided in a receiving groove which is formed on the end surface of the respective perpendicular wall, and the sealing material contacts with the bottom surface of a compression chamber of the other upright wall, thereby maintaining fluid tightness of the compression chamber.
Since a sealing property and a sliding-contact property of such a sealing material greatly affect the operational efficiency of the compressor, various researches have been conventionally made on sealing materials.
For example, a sealing material which can be molded by injection is disclosed in JP-A-3-273083, and consists of, by weight, 35 to 80% polyphenylene sulfide resin (hereinafter referred to as PPS), 10 to 35% fluorocarbon polymer, 5 to 15% pitch-system carbon fiber, and 5 to 15% organic powder. This sealing material is excellent in sliding-contact properties such as wear resistance, and moldability when it is used for scroll members made of an aluminum alloy. The pitch-system carbon fiber is employed because polyacrylonitrile-system PAN-system, carbon fiber can not provide a sufficient sealing property and has inferior moldability.
Also, JP-A-4-5492 and JP-A-6-25645 disclose sealing materials comprising liquid crystal polymer to which vitreous carbon (carbon whose fractured face has glassy luster: see JP-A-4-5492) or fluororesin and carbon fiber are added.
Recently, however, concerning scroll-type compressors, investigations have been made for using scroll members the surfaces of which are subjected to Tufram process or Ni-P plating to provide a surface hardness of not less than HV 500, thereby obtaining a high compression rate. When used for such hard scroll members, the above-mentioned conventional sealing materials involve a problem that they do not have an adequate wear resistance.